The invention relates to a thread delivery device, preferably for textile machines, comprising a stationary drum with a rotatable hollow shaft whereby a thread from a storage bobbin is delivered from a first face to a second face on the drum where a thread take-up member in the form of a circular take-up disc is rigidly mounted, with a thread eyelet arranged in the vicinity of its edge, on the rotatable hollow shaft for the tangential winding of an intermediate supply of thread on to the drum, said take-up means being slidable in the direction of the first face of the drum where the thread is drawn off the drum in the direction of and over the second face and fed to the working elements of the textile machine.
Such a thread delivery device was recently brought on to the market. The thread eyelet on this device is in the form of a tube one end of which is secured in the take-up disc. Its length is adapted so that during take-up the thread passing through the tube is reliably delivered to the section of the drum provided for storing the thread. This known thread delivery device has the disadvantage that while being drawn off the drum the thread can run into the section between the take-up disc and the adjacent part of the drum and become twisted there in certain cases, particularly at the beginning or end of the drawing-off operation. This inevitably results in thread breakage and stoppage of the device. There is a particularly high risk of such an occurrence with elastic yarns, for example synthetic stretch yarns.
There is another known thread delivery device of the described type in which an eyelet or guide acting as a thread take-up member is rigidly mounted on a rotor which is rigidly connected to the hollow shaft. the rotor supports a cover and the bearing for a freely rotatable reversing pulley the maximum expansion of which occurs in a radial plane of the rotor. The thread is guided via this pulley between the exit from the hollow shaft and the point of entry into the thread eyelet. This known thread delivery device is costly to construct. As in the case of the already marketed device described above, there is the same risk with this device, namely, that part of the thread to be unwound from the drum may run back and pass between the drum and the edge of the rotor running around said drum.
The problem for the present invention is to provide a thread delivery device of the initially described type in which there are provided simple means of preventing the thread which is wound off the drum under tension from passing into the area between the take-up disc and the drum.
The problem is solved in accordance with the invention by arranging an entire annular flange, on the take-up disc inside the thread guide, perpendicular to the disc and projecting towards the drum, the said flange being concentric with said drum and the section adjacent to the second face.
The annular flange is a component which can be economically manufactured and mounted on the other disc, and its advantages have a dual function:
It overlaps the area of the drum next to the second face in such a manner that if any of the thread being drawn off should run back, it cannot pass between the drum and take-up disc. The thread is thus drawn off in a trouble-free manner. Moreover, the annular flange causes the thread being passed through the thread eyelet to be reliably delivered beyond the lower end of the drum to the area of the drum intended for take-up.
The intermediate section between the annular flange and the take-up disc or pulley can advantageously partially overlap the opening of the thread eyelet. The thread leaving the thread eyelet therefore passes directly on to the outer surface of the annular flange which serves as a thread guide.
The intermediate section leading from the annular flange to the take-up disc can be rounded, which improves guiding of the thread to be taken up over the outer surface of the flange and prevents damage.
The commercially available thread delivery device described at the beginning of the specification comprises a thrust ring which is mounted on the drum and tilted relative to the axis thereof for the axial displacement of the intermediate thread supply on the drum. The annular flange on this type of thread delivery device preferably has an internal diameter slightly in excess of the external diameter of the thrust ring. This means that the annular flange renders the area between the take-up disc and thrust ring largely inaccessible to both parts of the thread leaving the drum under tension which may run back and to the thread which extends from the thread eyelet to the take-up area of the drum.
In a preferred embodiment the take-up disc is provided, along its circumference, in a manner known per se with an annular outer flange extending perpendicular thereto and towards the drum, and the edge of the outer flange directed away from the take-up disc supports an inwardly tapering protective ring. The outer flange forms a division between the unwinding thread and the thread in the take-up area such that mutual entanglement of the two threads is eliminated. At the same time it diverts the thread to be taken up in the direction of the drum, particularly via the conical protective ring. In addition, the inside of the outer flange combines with the outside of the annular flange to define a space which, similar to the tubular thread guide of the already commercially available thread delivery device, effects trouble-free delivery of the take-up thread to the drum. However, this space provides the take-up thread with a greater cross-section of travel. This thread delivery device can therefore also be used for extremely coarse yarns, i.e. those of large cross-section, as well as for different types of effect yarns. The diameter of the tubular thread guide in the known thread delivery device would have to be increased for such purposes, but this would result in an increase in the diameter of the take-up disc and therefore an increased diverting angle for the threads to be taken up and wound off, as well as increased space requirement.
Practical embodiments of the invention are illustrated in the drawings.